Single-Phase High Frequency Inverter Narrow Pulse High-Quality Modulation Method

Abstract

To analyze the narrow pulse issue of high-frequency single-phase two-level inverter running at high modulation ratio, the effects of modulation ratio, carrier frequency, and dead time on the narrow pulse under sinusoidal pulse width modulation (SPWM) strategy are examined, and the distribution law of the narrow pulse within the modulating wave period is derived. Based on this analysis, a high-quality modulation method without narrow pulses is proposed to eliminate narrow pulses within the modulation cycle of high-frequency inverters. To address the waveform distortion issue at the modulation peak and valley in this method, a three-beat carrier prediction method is designed to further improve the quality of the alternating current (AC) output waveform by modifying the modulation within the narrow pulse area. Finally, a single-phase full bridge inverter experimental platform is built to verify the feasibility and effectiveness of the proposed narrow pulse-free high-quality modulation method.

Keywords

• narrow pulse
• waveform distortion
• high-frequency inverter
• dead time
• single phase